Iris unguicularis (Algerian winter iris)

Iris Stylosa

Group: Iris
Other Names: Iris stylosa,
Algerian winter iris
Genus: Iris
Species: unguicularis
Family: Iridaceae

Foliage: Flowers:
Flowering Period: November to February


A vigorous evergreen perennial that brings much need colour to empty winter borders. These rhizomatous beardless irises enjoy a warm, sunny, well-drained aspect. If growing conditions are right, the narrow grassy leaves are topped with beautiful lilac or light blue honey-scented flowers, all winter long.


  • Habit: Clump-forming.
  • Leaves: Evergreen, dark-green.
  • Flowers: Highly fragrant. With colours ranging from violet, to mauve and pale blue, depending on variety.
  • Height: 1ft (30cm)
  • Spread: 1ft (30cm)
  • Aspect: Full sun in a warm sheltered position.
  • Hardiness: Hardy in the UK.
  • Soil Requirements: Well drained light garden soil (sandy, loam, chalk or clay).


Named varieties include 'Mary Barnard' (dark mauve) and 'Walter Butt' (pale blue).

Planting Context

Ideal for growing on banks, borders, flower beds and containers. Needs some protection during severe winters, so best grown under the protection of a south-facing wall. Useful plant for cut flowers.

Planting Iris unguicularis

Plant in September, in poor well drained soil, in a sunny sheltered spot. Sharp drainage is essential as the rhizomes will rot-off if the soil is too damp. Sprinkle a little bone meal over the area before planting.


Cut back leaves in June, with shears. This will allow the sun to ripen the rhizomes, which is essential for good flowering. Divide clumps once they become to large and congested.

Produces new flowers daily. Pick blooms regularly for cut flowers, just before the buds open (as open blooms can be damaged by severe weather or birds). An established clump can produce a continuing supply of cut flowers from November to February.


Propagate Iris unguicularis by division in summer/early autumn. Dig-up the clump and prize it into smallish pieces. If the clump is congested use two forks back-to-back. Replant the divisions immediately in their flowering positions.